It was bound to happen. Carriers have been cutting seats by reducing the number of flights they fly for the past few years, in a frantic effort to stay afloat: it's called "cutting capacity" and it's done because flying too many empty seats is a money loser.

Now as demand has waned airlines are prepared to drop even more seats -- tossing them overboard -- crowding us passengers ever closer to a sardine configuration. Bloomberg News cites a parallel from the 1940's: they say what's happening in the airline industry with seat cuts today is the "deepest retrenchment since World War II."

Thomsen, a Hollywood location photographer, says flying in the "old days" was better because you "could stretch out on all those empty seats." Nowadays, he rarely flies -- to be fair, that's partly so he can get a closer look at location possibilities, but it's also to avoid "the hassle of flying" and he proved that this summer by traveling 1,200 miles for a job -- from Los Angeles to Montana -- by car.

For him, the main "hassle" of flying is the overcrowding, and just look at the figures from the government's Bureau of Transportation Statistics (BTS).

These stats, known as "domestic available seat miles" show U.S. airlines this past June with the same available seat miles as a decade earlier in June 1999. Even worse, these numbers don't include the most recent round of seat cutbacks for the fall of 2009 and show a drop of more than 10 percent from their June 2005 highs. Only problem is, the U.S. population has increased during that same time period by 10 percent.

Will airlines add back seats as the economy bounces back? History says yes, but we have seen anything but historical trends lately, so I wouldn't bet on it.

Here's a tip: seat shortages can lead to overbooking, so don't volunteer to be "bumped" from an overbooked flight, unless your airline will guarantee you a seat on the next flight. If they tell you they'll get you out on the next available flight, you could be waiting for long time.

And now, another wrinkle: Did you know that "going green" may cost us seats? That environmental consciousness could result in "flight rationing"?

Not today, not tomorrow but maybe sooner than you think. Consider that the British Parliament Committee on Climate Change (CCC) said it expects air travel will double by the mid-century and if global warming is to be avoided (so the thinking goes), something must be done.

How? A cap, for starters. The CCC is calling for a cap on global aviation emissions at half the 2005 levels, by the year 2050.

According to the Financial Times, British Airways chief Willie Walsh says "in addition to this, the airline industry had agreed to improve CO2 efficiency by an average of 1.5 percent per year up to 2020 and stabilize net emissions from 2020."

The paper notes this agreement is supported by the 230 airlines in the International Air Transport Association, which includes U.S. based carriers.

All this seems pretty stringent, but many think it's necessary and maybe rationing will be, too.

The idea of rationing has been kicked around for a while; Lord Turner, the CCC's chairman, said in the past that people should be given "personal flight limits." There's that WW II parallel again; anyone remember the old coupon books you had to use in those bleak days of food and fuel rationing?

I don't know if CCC chief executive David Kennedy does, but he said recently: "You may want to go on holiday more than you do now. But you may not be able to do that in a carbon-constrained world."

Again, if this happens, it might not be for years, or decades. But all this "seat-snatching" underway by U.S. airlines could lead to a rationing of sorts, because the planes will get filled up sooner and those last-minute whims to "get away" may not be gratified as last-minute empty seats might be fewer and farther between.

Which leads me to this final thought: After a year of cheap airfare and decades of true democratization of flight, will commercial aviation turn into a right for the rich?

Or maybe it'll turn into a right for only those clever enough to make their plans well in advance. Remember, to win at musical chairs, you have to be a little faster than the others. Grabbing an airline seat may not be so different.

This work is the opinion of the columnist and in no way reflects the opinion of ABC News.

Rick Seaney is one of the country's leading experts on airfare, giving interviews and analysis to news organizations, including ABC News, The New York Times, The Wall Street Journal, Reuters, The Associated Press and Bloomberg. His Web site FareCompare.com offers consumers free, new-generation software, combined with expert insider tips to find the best airline ticket deal.